1. Field of the Invention
The invention relates to a device for monitoring the end dropout of cigarettes.
2. Description of the Prior Art
Cigarettes with ends inadequately filled with tobacco should be automatically detected in cigarette production and separated out because when the cigarettes are removed from a pack tobacco particles drop out of the ends, the so-called "end dropout", and this quality defect is immediately noticed by the smoker. In particular, the manufacturing should be carried out in such a manner that the ends of the finished cigarettes are adequately and permanently filled with tobacco.
Test methods are already known in which mechanical test pins are pressed against the individual cigarette ends and from the magnitude of the penetration depth it can be concluded whether the filling of the cigarette ends is adequate (cf. for example DE-AS No. 1,257,651). The resulting mechanical influence of the cigarette ends by the measurement is however undesirable.
DE-PS No. 2,343,668 further discloses a capacitive measuring arrangement having at least two electrodes connected to a high-frequency voltage source; the position of the electrodes with respect to the cigarette ends is chosen so that at the measuring instant a high-frequency field emanating therefrom traverses the individual cigarette ends.
It is further known to detect incompletely filled cigarette ends by the intensity of a light beam reflected by the end of the cigarette, cf. DE-OS No. 2,813,866, DE-OS No. 2,236,218 and DE-OS No. 3,146,507. A combination of optical/mechanical measuring means is disclosed in DE-OS No. 2,060,887, according to which the cigarette ends are compressed laterally by means of compressed air, the extent of the compression being monitored by means of a light beam.
The aforementioned test methods carried out in the course of continuous cigarette production all have the disadvantage that they only provide information on the filling state of the respective cigarette end at a certain point of time but no information on the loss of tobacco mass due to a defined mechanical stressing of the cigarettes.
A device which does permit this, although only batchwise in laboratory operation, is known to the expert in the form of the "end test device" of the company Heinrich Borgwaldt, Hamburg. A specific number of cigarettes, for example simultaneously 50 cigarettes, are subjected in an oval container whose walls consist of round rods to a rolling and dropping movement. During a predetermined period of time or number of revolutions the tobacco particles dropping out of the cigarette ends are collected.
After a predetermined period of time, for example after three minutes, the collected tobacco particles are weighed so that the average end dropout for a predetermined number of cigarettes can be determined.
The advantage of this laboratory method is its relatively high accuracy of information; a disadvantage however is that it can only be used for random samples, i.e. the continuous monitoring of all cigarettes made in cigarette production is not possible.